In the Shadow of your Brilliance
by Neldoreth
Summary: What bewildered John the most was the woman sitting right in front of Sherlock, someone John barely knew anything about. A woman now wearing one of Sherlock's expensive silk shirts. A woman kissing Sherlock's lips. - Find out the story behind that scene. A bit dark, not Johnlock, contains OC


Disclaimer: Everything belongs to the BBC, Moffat, Gatiss and Doyle ;), but the OC is all mine!

Info: This story contains an OC, is not Johnlock and english is not my first language - but I tried very hard, so please be kind :).

Corrections and reviews are very welcome!

* * *

**In the Shadow of your Brilliance**

John Watson glanced through the half-opened kitchen door and stopped. Despite the golden rays that bathed their living room in a warm golden light, he felt a cold shiver down his spine.

It was early morning and the coffee machine gave bubbling noises, telling that coffee was ready and his toast was getting lukewarm while he was caught in the strange scene that took place in their flat.

His flat-mate, the brilliant consulting detective, was sitting on the table, his back upright, eyes observing, hands placed under his chin, his fingertips touching his upper lip. The dark locks shimmered golden in the raising sunlight and his usually pale, flawless skin seemed warm and soft now.

But the sight of Sherlock Homes, looking more like the bronze statue of an ancient fire god, than like the highly intelligent detective he actually was, wasn't what bewildered John the most.

It was the woman sitting right in front of Sherlock, on the chair John used to sit. She wore not much more than very short pants, sitting on her crossed, naked legs and a purple shirt, that definitely was one of Sherlock's expensive silk shirts. Long black locks curled around her sharply drawn face, the sunlight only visible on her high cheekbones and on the tip of her pointy nose. She was silently speaking, moving a pair of perfect, pink lips slowly while talking to the detective in front of her.

John was aware who she was. Well, he almost did. Sherlock had come up with a case yesterday and had dragged his flat-mate with him, out into the cold, rainy night, right into a vibrating, deafening nightclub. Sherlock, tall and black haired, wearing his dark coat, had disappeared within the dancing people dressed in dark leather, short skirts. Some of them had even hid their eyes behind sunglasses. John had felt uncomfortable with his bright blue shirt, bluejeans and new brown shoes, but to his luck, they hadn't remained very long.

Sherlock had found quickly who he had been searching for. He had grabbed a young woman at the shoulders, dressed in a far too short leather mini skirt and a sparkling backless top. She had been yelling at him all their way out, cursing, apparently exactly knowing who he was. And obviously drunk and drugged to the eyeballs. Her long black hair had stuck on her sweaty forehead and her voice had already been hoarse from drinking.

Claire looked much better now, John thought. But after some hours of sleep, a shower and some aspirin, her eyelids were still heavy and dark shadows under her eyes revealed that she had had a rough night. But for all that, there was a kind of graceful aura around her, that revealed a kind-hearted but fragile soul behind that superficial rebelliousness. Without the flickering lights on her tight dancing dress, the unsteady gait and the curses floating out of her mouth, she now seemed like a mosaic out of shattered smoke glass.

Sherlock hadn't told him very much about the girl called Claire Roberts, but the name of his brother was mentioned and that someone should keep a wary eye on her. They had dragged her home and John had had a hard time trying to keep her up on her feet, ignoring her permanent protest.

But at least he had managed to put her into Sherlocks bed. John was still wondering why the detective had given up his sacred sleeping-place so easily. Claire had passed out almost immediately, while John had waited by her side, constantly checking her pulse and breathing until he had been sure, that she was sound asleep and would not throw up.

Now she was awake, the mysterious woman, as thin as her opponent, gesturing with her hands, while Sherlock was still observing her, drinking in her face, as if she was some of his experiments.

Maybe she was?

The sight of these two people, bathed in sunlight and shadow, both inscrutable to John Watson, distracted his attention away from everything else. But he couldn't have foreseen, what happened next.

Claire suddenly rose from her chair, kneeling on her slender legs and bent over the table to place a perfect, long lasting kiss on Sherlock's motionless lips.

* * *

Her lips were far too warm. A heat, aroused from a fever, caused by a slight cold she had gotten yesterday, coming out of that nightclub covered in sweat and stumbling through the London rain. Sherlock could also tell by the damp hairline, the rosy cheeks and the cold fingers, that shivered barely noticeable, though the rest of her skin was burning.

Those lips weren't strangers and he had kissed them before. A long term remembrance he had tried to forget, tried to erase, to make room for other things. But his brain wasn't able to do so. He never forgot anything that was important to him and unfortunately she had been important. Still was.

Sherlock didn't move while Claire kissed him. Her scent filled the air he was breathing, a scent, that was his own, because she had used his shower gel and shampoo. His eyes were open, while she had hers shut. Her face was blurry, but he recognized the black locks on his right cheek, that were so alike as his untameable hair.

He didn't move closer, but didn't draw back either, waiting until her hot breath retreated from his face. A little bit of saliva was left on his upper lip, as she finally opened her eyes and held her position for a second, giving him a second to take a very close look on the soft lines on her still so young face. There were so many emotions mixing in her tired face and in the familiar bright blue eyes, but he wasn't able to pass back one of them.

Claire had been threatened by some kind of dangerous stalker, but, as she always did, hadn't cared very much about it. But Mycroft had known better. He had had a watchful eye on her, since they had seen her the last time. What was some years ago. 5 years, 3 months and 16 days, to be exact.

Everything that had happened before that day, was a story he had left far far behind and Sherlock had been hoping she also had. Especially as Mycroft had asked him to watch out for her, to take care of the accident his father was to blame for. To take care of their half-sister, five years younger than Sherlock himself.

* * *

John breathed deeply took the tray with the coffee and his cold toast on it and pushed the door to the living-room open. Claire flinched at his interference, but Sherlock was calm as ever.

"Good morning." John said merrily, as if nothing had happened. Claire fell back into the chair and ran her fingers through her hair, obviously embarrassed. The bright blue eyes, a cold and stunning colour, like glaciers reflecting summer sky, looked still tired and watery from too much alcohol.

She looked away and mumbled a silent "Morning.". Then she stood up, straightened Sherlock's shirt over her hips and curled her long hair between her fingers.

"Coffee?" John asked but Claire shook her head, wrinkled her nose and swallowed hard, as if she was sick.

"Not yet, thanks." she managed to say. "I'm going to get some more sleep. Sherlock?" she asked, looking directly at the detective.

He gave her a hard look, but nodded slightly. "I won't need my bed anyway. Get some sleep, we talk later." Sherlock said in an undertone of arrogance.

Claire tiptoed past John, who was still holding the tray in his hands, and looked shyly into his face on eye level, before she disappeared into Sherlock's room.

The shut of the door was John's cue. He put down his breakfast, fell onto the chair, still warm from Claire's slender form and stared at Sherlock, who was now typing something into his phone.

"Now." John started, but got no attention from his flat-mate. The sun was rising quickly now and the golden rays in his hair cooled and turned his face back from soft bronze to stern marble.

"Will you tell me a bit more about that pretty girl, sneaking around in your clothes, kissing you in the morning?" John poured milk into his coffee and tried to sound, as if he was chatting about the weather.

Sherlock still looked at his phone. "What would you like to know?"

John took a sip and raised his eyebrows. "First, who is she? You haven't told me yet." he said.

"She is my sister." Sherlock said dryly and emotionless after a short unusual pause.

John almost dropped his cup. He froze again and stared at Sherlock with an open mouth, until his opponent looked up to him and put his phone onto the table. "My half-sister to be exact. I supposed you had already recognized that?"

John thought about his words while he tried to breathe again. There had been a resemblance, the black curls, the bright, piercing eyes and the prominent cheekbones. But he had not – .

"But she kissed you." John said, not really knowing why that was the first thing coming to his mind.

"Obvious." Sherlock stated and pursed his lips, as if to recall the feeling she has left on his mouth.

"Why?" asked John stretched and was completely aware that he looked like an idiot, with his mouth and eyes wide open, the cup still raised in front of his face.

"It's a long story." Sherlock mumbled, seemingly not willing to go further into detail.

"We've got time." John said firmly, pulled himself together and finally set down his cup.

* * *

_5 years, 3 months and 15 days ago_

The cold, bright light in the lab forced Sherlock to form his eyes to slits as he watched the ashes of the Pink Elephant Vanilla cigarette he had stolen from one of the hospital employees at the reception desk. Within five seconds he recognized twenty differences to the Benson & Hedges Black he had observed that morning.

He rubbed the ashes between his fingers and sniffed at it, as he heard the sound of the door. Sherlock didn't look up, too busy with his experiment, but he quickly recognized, who had just entered the lab.

"Hey Sherlock." her voice sounded through the room, a dark tone, husky from smoking and cold air, slightly nasal, maybe from the weather or from crying. High heels moved closer and Sherlock granted her a quick glance from the side.

Claire hadn't changed very much. Her hair was still a mess of dark, thick curls, reaching down to her waist. Beautiful great eyes watched him closely, looking sad, while her pale coloured mouth was formed into a fake smile. An already healing bruise showed off on her left cheekbone, she had bit her lips, drawing blood, and had removed a ring through her nasal wing two weeks ago. She hadn't slept much, maybe two hours the last night and was obviously lacking vitamin b.

The rest of her appearance was neat and her walk graceful as ever, seducing, slowly. Claire was still pretty, smooth and fragile.

"You need money." Sherlock stated and faced the ashes in front of him again.

Claire shook her head. "I wanted to see you." she said quietly, an urging undertone in her voice.

"Because you need money and Mycroft had denied your request." The detective repeated and stiffened as she laid her cold fingers, too thin and long for a girl like her, on his left hand, that was holding the culture dish.

Sherlock sighed, but turned to her, looking up, because he was sitting and she stood right in front of him. Her clothes were still cheap but tasty, grey trousers and a silver shirt, underlining her icy, shadowed eyes. A smell of vanilla radiated from her bright skin.

"Who hit you?" he asked, nodding his head forward to the bruise on her face.

Claire shrug her shoulders. "I hit him first."

Sherlock had already realized the small scratches on her knuckles.

"This is not why I am here, Sherlock. Do you remember what we were talking about last time I visited you?" she asked.

"Of course I do." Sherlock answered, slightly angered, that she was always asking such stupid questions. She knew him very much and these rhetorical chattering lead to nothing. It has been two years since he had last seen her, but he remembered every word.

They had talked about a poison he had explored then. It had been used on an incident, Sherlock had read about in the newspaper. Unsuccessfully he had tried to convince the police, that it had not been suicide, but a murder out of jealousy.

Every time he did this they told him to stay away, to be quiet, but there was one man, that listened to him from time to time. Detective Lestrade had conducted a study and eventually they had figured out that the girl had actually been poisoned with a form of parathion, a toxic used in bug repellent. Sherlock had reproduced it to emphasize his thesis, though it was not allowed to use or produce the toxic any more.

"Would you still like to know how exactly the poison works on the human body?" Claire asked bluntly, her eyes glistening for a second.

Sherlock frowned. "I already know. I read everything about it and we could prove it in this woman's blood." he said with incomprehension.

Claire's fingers wandered from his wrist up his arms, stroke along his neck and eventually rested on his chin. Her touch made him shiver inside, as it always had.

He had never found out what it was, that attracted him to her. Sherlock was never attracted to anything or anybody, except it concerned an experiment or a murder.

But Claire caused something in his nervous system other people would describe as arousal. His heart beat faster, pumping more blood through his veins, widening his pupils and his senses. His whole body reacted to that woman's slightest touch and that was the point he flinched back a bit to escape that fingers, that threatened his hard working and highly functional mind.

"Still afraid of me, Sherlock." she purred. "I'm your sister, you don't have to be."

That was worst of all. The blood in their veins was about 50 percent the same. She looked so alike him, it was frightening and had stunned a lot of people, who got to know that awkward chapter of his family history.

Because of Sherlock's mother they hadn't grown up together, but Claire had always been a part of their lives, visiting on holidays, stalking after her older half-brother, begging him to explain to her, how he could read anyone who walked past them.

But she never understood. Sherlock was all logic, Claire was all emotion. She had remained a mystery to him all those years, because of her flaming temperament, her witty mood and the irrational decisions she used to make. His little sister was like a storm, sweeping through him every time she appeared, leaving a mess behind, forcing his mind to order everything inside him from the beginning on.

"What do you want from me then?" Sherlock asked, relieved that his voice was steady and calm as ever, not showing his mixed feelings.

Claire leaned closer, laying her hand onto his knees, slowly rubbing his thigh. "I want to be your experiment."

* * *

"So she is the daughter of your father and another woman. And there is someone after her, so you'll take care of her until Mycroft has got rid of him." John summarized what Sherlock had just told him, short and fact by fact. But he still couldn't understand why she had kissed him.

"But Sherlock – I have seen and shared kisses before." John said with a smile, thinking about how long it had been, that he had kissed a girl recently. The quick thought of how it would feel to kiss the lips of Sherlocks pretty half-sister came to his mind, but the similarity to Sherlocks own lips puzzled him too much to get closer into that thought. "And as far as I could see, that was not a sisterly kiss."

Sherlock frowned and his bright eyes formed into slits. "Why have you been eavesdropping at all John?" he was asking, still slightly angry.

"Well you haven't been hiding very well." John said with a chuckle.

Sherlock sighed heavily. "She obviously has a crush on me. We didn't grew up together like brother and sister. I can't tell you why she sees me like that."

John raised his eyebrows in surprise. "You can't?"

Sherlocks lips got thinner. He was obviously upset by the fact, that there was a case he couldn't solve.

"She's so confusing. She _is_ confused. I can't predict what she is about to do, what goes on in her head. I can tell you what kind of tooth paste she usually uses, that she hasn't visited her mother in weeks, but I can't tell you why she's acting like that." He picked up his phone again and looked at it.

But John wasn't done yet. "I'm wondering, why you haven't stopped that? Maybe you... like it?"

He was searching for some reaction in Sherlocks face. Perhaps there was the slightest of blushes on his cheeks, a split second that he held his breath, the smallest of twitches in one of his fingers, that grabbed the phone a tiny bit too hard.

"She managed to seduced me." Sherlock said simply. "More then once."

* * *

_5 years, 3 months and 15 days ago_

Sherlock was prepared. He had an antidote, adrenaline and, to anticipate the worst, a defibrillator at hand. His laptop was ready as was his medical equipment. The far too small flat he lived in was cleaned up at least for this experiment, but despite all of his efforts, Claire seemed completely unimpressed.

Everything she had contributed was her MP3 player and herself. She leaned into the cushions on his couch, staring out of the window into the late night. Claire was so absent minded, Sherlock wasn't sure if she even remembered, that he had injected her a possibly deadly poison into her system some time ago.

"It has been 3 hours and 24 minutes now. Tell me how yo feel." Sherlock observed his half-sister from a chair at his desk, reached out for her wrist to check her pulse. Her skin was getting colder and he assumed that her lack of concentration arose from the poison.

"I feel sick. Like – from too much sugar." she mumbled, her tongue was already heavy and her lips too weak to articulate accurately. Sherlock typed his observations on his laptop.

"How long has it been?" Claire asked and Sherlock stopped. 'Lack of concentration, slight amnesia.' he typed.

"3 hours and 25 minutes." he told her again.

"How long will it take, what do you think?" she asked and looked at Sherlock. Her glance was straight, but the eyes watery and she blinked.

"About 20 minutes." Sherlock assumed. He hadn't experienced the effect of the poison on a living body, so he could only guess. Something he really hated. The detective in him was curious and exited to get to know the proceedings, but there was something deeply buried in his brotherly mind that told him something was wrong.

Of course it was wrong to inject his little sister a deadly toxic. But there was a 5 percent chance of her getting killed by it. Sherlock was ready to do whatever was necessary to get the poison out of her body quickly, as soon as she would pass out. He had everything under control.

"Why don't you come over to me?" Claire asked, her voice clearer now. She patted the seat next to her. Sherlock sighed heavily. He knew what she was after, knew the blunt glistening in her eyes and the way she licked her lips, when she was excited.

But his flat was dark and he had difficulties to look at her very closely, so Sherlock grabbed his laptop, set it down on the table in front of the couch and took seat next to his half-sister.

Through the earphones of her MP3 player, that laid loosely around her neck, he could hear some of the music she was listening to, a silent choir in the background, a piano playing, a male voice.

"I could have played on the violin if music relaxes you." he stated but Claire just smiled sorrowful. She turned to him, leaned forward and rest her head on one hand.

"I like it when your playing, but the violin makes me sad." she took one of her earphones and stuck it into Sherlocks ear. The music was not loud enough to drown her voice, but he could have read from her lips anyway. "It's a Scottish band. I can't remember what they are called, but I love that song."

'Amnesia is increasing steadily' Sherlock noticed in his mind. Claire closed her eyes and leaned her head into her hand.

"Do you think Dad will miss me?" she mumbled, moving her head with the melody.

"Don't be ridiculous." Sherlock stated.

"I'm not." Claire chuckled silently. "Why do you always say that?"

"You're far more clever than that. Don't ask such silly questions all the time."

"So you think I'm clever" she seemed to be surprised, her eyebrows rose above her still closed eyes.

"You are. But you never use you're brain." He was deadly serious, but Claire smiled at him, warm-hearted and careless. She thought about his words and returned to the subject.

"So he won't." Claire supposed and Sherlock shook his head.

"He will not miss you, because there won't be anything to miss." He checked her pulse again. It was growing faster. Her face slowly went pale and there were little twitches in her hands.

"But I'm going to die." she whispered, her voice barely audible through the music.

"You are not." Sherlock said, frowning. A tear was glistening between her closed eyelashes. She was so close, he could touch her, comfort her at least a tiny bit, but he didn't. She would distract him from his observations.

Except the silent noises from her earphones everything around them was quiet. No one on the streets, the neighbours already asleep. The flat was warm and the way they sat on the couch remembered Sherlock of a different situation some years ago.

Everyone had been out, neither his mother nor Mycroft had been at home. He had been reading in his favourite armchair, Claire next to him on the armrest watching telly.

Without warning she had slipped down to him, had grabbed his book and had kissed him on the cheek. He had been too surprised to move and so he hadn't held her back when she had straddled him, placing her slender legs on each side of his thighs and her mouth on his, kissing him so desperately, his mind ran completely empty within one second.

From that moment on they had this thing going on. She had slipped into his bed at midnight, had assaulted him under the shower or had invited him to her new apartment, making him completely loosing his sanity, every time he was with her.

But she never told him, why she was doing it. His half-sister just shrugged her shoulders and said that she enjoyed his very presence and that she was the only person in the world to make him going completely crazy.

He had never been with another woman and he didn't intended to do so. Yet Sherlock had been relieved when she had left Britain for a while, leaving him alone to his studies and finally finishing this completely wrong and irritating relationship, or whatever it was.

Claire moved now and took a packet of mints out of her pockets and threw two of them into her mouth. Then she rushed forward without warning and kissed him, hard and desperate, like that first time, Sherlock had just been thinking about.

She laid her hands onto his chest and opened the first two buttons of his shirt and he allowed her to do so. Sherlocks heart was pounding fast against her cold and damp palm and Claire gave a whimper, that ran down his spine like a trace of fire, as she demanded entrance into his mouth. Her tongue was skilful and he almost forgot what they were here for, as he moved forward and leaned into her passionate kiss.

He wrapped his arms around her thin body and buried one hand in her thick locks. The heavy breathing of both of them mingled with the sound of the music and for a second Sherlock yielded to the demands of his body and concentrated on the joy her slender form pressed against his chest caused him.

One of her mints wandered into his mouth while her tongue softly stroke his and he swallowed unintentionally. The lack of the typical mint-taste reached his mind, but as he actually realized it, it was too late.

His eyes, which he had closed without even noticing, snapped open and Claire sighed aloud, as he grabbed her by the shoulders and to loosen her grip at him.

"What was that?" he almost yelled at her and ripped the earphone out of his ear. Claire looked confused, licked her lips, red and wet from kissing, but Sherlock read her face.

"What did you give me?" he asked more firmly, holding her slender shoulders in a stony grip.

She stuttered and blinked, obviously weak and confused. "I'm sorry Sherlock."

There was something going on and as Sherlock finally deduced what it was, it hit him like the slam of a hammer.

"It is a strong anaesthetic. Works within seconds." she whispered and grabbed both of his hands. Her fingers interlaced with his. "I know you wouldn't have let me do this." She was picking every single word slowly, the anaesthetic operating faster in her system than in his own. "You would never let me die. But I want to."

The grip of her fingers loosened and Claire suddenly collapsed into the cushions, her head on the back of the couch, looking up to her older brother, an apologizing glance in her icy eyes.

Fast blood rushed in Sherlock ears, the silence became louder, the piano on her MP3 player now a chaotic melody, he couldn't follow any more. His vision blurred and as Sherlock felt that every muscle in his body was going to relax within a few seconds, he jumped to move over to the desk, searching for his phone.

On his way his feet gave in and he stumbled, went down onto his knees and lost control over his limps. The left side of his face hit the dusty carpet, the pain in his collapsed bones didn't reach his brain any more. But the sight of Claire half laying on the couch now, her chin resting on her chest, the beautiful eyes closed, red lips going pale, made him crawl, using the last of his strength to reach his phone.

"I won't – " he whispered to himself, desperately holding onto the thought, that he could not, no, would never ever allow her to die. Not like that. Claire, the only woman in this world that had touched him in a way he never thought someone could.

The woman that had managed to deceive and sedate him, so he could not save her life.

Sherlocks fingers got hold of the edge of his phone and as he finally lost his vision and the feeling in his limbs, his last thought was, that she would die because of him, if he didn't managed to – .

* * *

Lestrade had been alarmed by the call from Sherlock Holmes, who usually never called him, not to mention, that he didn't answered when Lestrade was asking what was wrong. Before the poison had completely destroyed Claire's nervous system she had been carried into the hospital, where they eventually saved her life.

Sherlock woke up in a bed next to her, recovering quickly and leaving the hospital within a few hours, before Claire had recovered consciousness again. He hadn't been prosecuted for the poisoning, after he had explained the complete incident to Lestrade.

Also he hadn't visited his little sister once. She had played him off, had tried to use him for a suicide attempt and that had made him so upset, he hadn't been able to look into her eyes any more.

At the other side of the table John looked at him compassionate, but to severe for Sherlock to rebuke him for his unnecessary pity. Usually they didn't talk about such private things, but Sherlock was sure, that his flat-mate would not dwell on the subject any longer.

Sherlocks phone peeped and he looked at the message from his brother.

'Tomorrow you will be rid of her. Don't try to kill her before then. MH'

Another day and one more night with Claire in close proximity. Sherlock hoped that there would be a case coming up, so he could leave the flat without the need of an excuse.

Well, obviously he would find something to distract him the next 24 hours. He could ask John to take care of her, while he was gone. Maybe the good-hearted doctor would get along better with her messy personality.

"I will be out today. Could you look after her?" Sherlock asked and received a knowing look from his opponent.

"Sure." John just said, emptied his cup and reached for the newspaper, as he did every morning. Case closed. Sherlock smiled thankfully.

* * *

John was half asleep in his bed, as he heard the door to their flat shut. Sherlocks steps sounded through the living room, something was rattling and John looked at his watch.

He had been gone for at least 16 hours, just to avoid Claire who had been sleeping half of the day. Later she had joined John to watch some television and talk a little about nothing in particular.

She was a kind person, quiet, but cheeky and almost as eloquent as her brother, but not quiet as harsh as him. While John talked to her he came to the conclusion, that she was obviously depressive, balancing on a dangerous cliff of self-hatred and the will to keep her mind sane. Probably a result of her difficult childhood, but John assumed that it had definitely something to do with Sherlock Holmes.

In the late evening John had got a message from Sherlock, that Claire's stalker had been caught. As he had told her so, she had reacted with a joyless laugh.

"It was nice to meet you John." she had said, pressing a little kiss on his cheek and disappeared into Sherlocks room, leaving a presence behind, that made John unbearably sad. He could only guess what she had endured all those years, desperately in love with a brilliant mind.

A brilliant mind that was her brother. That didn't had a clue how she really felt within her heart, how bruised she was inside, leading a life within reach of Sherlock Holmes, but not being allowed to love him like she did.

As everything went quiet down in the living room John supposed, that Sherlock would sleep another night on the couch, or wouldn't sleep at all.

But on the other hand the doctor wasn't surprised as he heard the door of Sherlocks bedroom, followed by complete silence again.

He turned around in his bed and while he was falling asleep, John Watson recalled the feeling of soft, warm lips touching his cheek, tasting her name on his tongue. Claire, sister of the brilliant Sherlock Holmes. Dying slowly in the shadow of the great detective. Dying slowly in his arms.

**END**


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